Compilare: user.cpp: In function ‘void dfs(int, int)’: user.cpp:11:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<G[nod].size();++i) ^ user.cpp: In function ‘int main()’: user.cpp:21:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("dosare.in","r",stdin); ^ user.cpp:22:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("dosare.out","w",stdout); ^ user.cpp:23:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&N); ^ user.cpp:25:72: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] for(int i=2;i<=N;++i)scanf("%d",&x),v[i].val=x,++v[x].nr,v[i].ind=i; ^ user.cpp:30:47: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] for(int i=1;i<=N;++i)scanf("%d",&v[i].val); ^